The present invention relates generally to laundry feeding machines, and more particularly, to loading, spreading, and feeding mechanisms which rapidly and accurately transfer and spread a sheet of laundry and place it onto a conveyor for subsequent processing by ironing machines, folding machines or the like.
After laundry articles such as bed sheets, table linens, blankets, or the like are washed in a laundry facility, they are typically fed into a flatwork ironer and automatic folder. The flatwork ironer dries and irons the wet sheets and the automatic folder folds and cross-folds the sheets into a neat package for use in hotels, hospitals, or the like. In order to obtain a neatly folded, unwrinkled package, it is important that the sheet be presented to the ironer with no wrinkles or folds and with the leading edge square. In the past, skilled operators have been employed to manually spread the sheet apart and place it in the ironer by hand. However, the use of operators tends to slow the output of the ironer and can lead to inaccurate placement of the sheet in the ironer. To overcome this difficulty, modern laundry facilities use an automatic spreader feeder apparatus to allow more rapid and accurate feeding of the sheets into the ironer.
These spreader feeder machines typically include a continuously moving conveyor on which the sheets are automatically laid with their leading edges perpendicular to the conveyor belts. In order to position the sheet for placement onto the conveyor, a pair of clamps are typically employed to grip opposing top corners of the sheet. The clamps are then moved apart by one or more endless belts to spread the sheet in front of the conveyor. To further assist in spreading of the sheet, a lower portion of the sheet is often spread between opposing pairs of lower endless flexible belts. Once the sheet is spread to the desired position, the clamps release the corners of the sheet and the upper portion of the sheet is forced onto the conveyor. The conveyor then advances the sheet to the ironer or other processing equipment. Various machines of this general type are disclosed in U.S. Pat. Nos. 4,885,853 to McCabe and 4,106,227 to Allen et al., and U.S. Pat. Nos. 4,967,495, 4,345,391, 3,421,756, and 3,376,036 to Weir.
In the machines disclosed in the '391, '756 and '036 patents to Weir, one clamp is attached to the upper run of an endless belt and another clamp is attached to the lower run of the belt. Thus, movement of the belt in one direction moves the clamps apart, and movement of the belt in the opposite direction moves the clamps together. In such devices where one or more belts are used to move the clamps in opposite directions, a reversible driving mechanism is provided to move the belt(s) in the desired direction. For example, the driving mechanism disclosed in the '756 patent to Weir is a friction clutch with a reversible electric motor or a double-acting pneumatic ram coupled to one of the clamps. To arrest the movement of the belt, a solenoid operated brake acts on the belt when a signal is received that the leading edge of the sheet has reached a certain height indicating a fully spread sheet. In the '227 patent to Allen et al., a reversible clutch-brake unit is provided to move the belts in the desired direction. Such complicated driving mechanisms are costly and difficult to maintain, and can be unreliable with extended use. In addition, the abrupt braking action of these mechanisms at a single end position can lead to inaccurate positioning and tensioning of the sheet. Such a braking action in conjunction with a constant speed drive can also make it difficult to retrieve a sheet which gets caught somewhere in the machinery. Another difficulty can occur when the sheet is not properly transferred to the clamps or when a corner portion of the sheet is released during the spreading operation. In these situations, one corner portion of the sheet is typically moved to the end position which can cause excessive downtime.
In some spreader feeder machines, the upper portion of the sheet is blown onto the conveyor after being released by the clamps. The '227 patent, for example, discloses a plurality of blowers positioned above the conveyor for blowing the sheet onto the conveyor. In other machines, the upper portion of the sheet is drawn onto the conveyor by a vacuum having an upwardly facing suction duct below the conveyor. A vacuum of this type is disclosed in U.S. Pat. Nos. 4,967,495 and 4,729,181 to Weir. In addition to forcing the upper portion or leading edge of the sheet onto the conveyor, it is desirable to hold down the lower portion or trailing edge of the sheet to keep the sheet taut as it moves on the conveyor to ensure a flat laydown of the sheet on the conveyor.
In order to facilitate loading of the sheets by an operator, some spreader feeder machines include mechanisms for transferring the clamps between the spreading area immediately in front of the conveyor and a position forwardly of the spreading area. This makes it easier and safer for an operator to place the corners of the sheet in the clamps. Typically, the clamps are mounted on a transverse beam which '15 in turn moves on rollers in a linear horizontal direction toward and away from the spreading area. In some of these machines, the sheets are loaded onto a separate clip and the clamps are adapted to remove the sheet from the clip. Machines of this type are disclosed in the '036 patent to Weir and U.S. Pat. No. 3,664,046 to Thompson. Because the entire spreading mechanisms of these devices are moved forwardly and rearwardly along with the beam, they tend to be cumbersome, costly, and inefficient.
Various spreader feeder machines are also designed to accommodate three operators at different loading stations. This increases the speed at which the sheets can be fed to the spreader clamps which improves the overall output of the spreader feeder machine. For example, the machines disclosed in the '036 and '046 patents include clips mounted on arms which swing laterally from an outer position to a center position where the clamps pick up the sheet. Because the outer swing arms move laterally to position the clips in the center area, the number of loading stations is limited to three. In addition, the moving parts may impede the motion of the operators and may present a safety risk during rapid loading of the sheets. Accordingly, it is desirable to provide more work stations with more reliable, faster, and safer loading mechanisms.
It is therefore desirable to provide a machine which facilitates user interface and operates more rapidly than other spreader feeder machines. It is also desirable to reduce the complexity of the machine and thereby facilitate reliability and maintenance and reduce costs of the machine.